Australian Patent Specification 618545 (AU-B-19935/88) discloses a gyratory crushing apparatus including a bowl and a crushing head. A support assembly is arranged to support the head at opposite axial ends thereof to dispose the head at an angle to the central axis of the bowl. The crushing head has a gyratory axis which intersects with the central axis of the bowl at a pivot point located at the bottom of the crushing head. The crushing apparatus further includes a drive assembly for driving the crushing head about the pivot point causing the top of the crushing head to oscillate in a direction substantially transverse to the central axis of the bowl and to cause the bottom of the crushing head to oscillate predominantly in a direction parallel to the central axis. In the illustrated embodiments of specification 618545, the support assembly includes a rotatable shaft connected at one axial end to the drive assembly and journalled or pin mounted at its other axial end to an upper end of the crushing head, and a universally pivotable joint including a knuckle on which a lower end of the head is seated. The connection between the rotatable shaft and the crushing head is arranged to permit relative rotational movement between the shaft and the head.
A problem with the support assembly disclosed in specification 618545 is that precise adjustment is required to establish and maintain the proper geometric relationship between the vertical axis of the bowl, the rotatable shaft and the lower crushing head knuckle. As it has been found difficult to achieve the required precision with reliability or repeatability, the apparatus has not always performed satisfactorily and can suffer premature mechanical damage.
An aim of the present invention is to provide an improved support assembly for a gyratory crushing apparatus which at least ameliorates the above problem.